temp_controller2.cpp

// -------------------- Stage Durations in milliseconds --------------------
const unsigned long stageDurations[] = {
  4UL * 60UL * 60UL * 1000UL, // Stage 1
  6UL * 60UL * 60UL * 1000UL, // Stage 2
  8UL * 60UL * 60UL * 1000UL, // Stage 3
  3UL * 60UL * 60UL * 1000UL, // Stage 4
  1UL * 60UL * 60UL * 1000UL, // Stage 5
  4UL * 60UL * 60UL * 1000UL  // Stage 6
};

// -------------------- Stage Target Temperatures --------------------
const float stageTemps[] = {
  20.0, // Stage 1
  25.0, // Stage 2
  30.0, // Stage 3
  40.0, // Stage 4
  50.0, // Stage 5
  60.0  // Stage 6
};

// -------------------- Includes --------------------
#include <LiquidCrystal.h>
#include <OneWire.h>
#include <DallasTemperature.h>

// -------------------- LCD Setup --------------------
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

// -------------------- Temperature Sensors --------------------
// Channel 1 on pin 7
#define ONE_WIRE_BUS_1 7
OneWire oneWire1(ONE_WIRE_BUS_1);
DallasTemperature sensor1(&oneWire1);

// Channel 2 on pin 6
#define ONE_WIRE_BUS_2 6
OneWire oneWire2(ONE_WIRE_BUS_2);
DallasTemperature sensor2(&oneWire2);

// -------------------- Heater Relay Pins --------------------
#define HEATER_PIN_1 9
#define HEATER_PIN_2 8

// -------------------- Timing --------------------
unsigned long startTime;
unsigned long lastLcdInit = 0;
const int numStages = sizeof(stageDurations) / sizeof(stageDurations[0]);

// -------------------- Global Variables --------------------
float targetTemp = 0.0;
bool finished = false;
bool heater1On = false;
bool heater2On = false;
bool blinkState = false;     // For blinking indicator
int blinkCounter = 0;        // Count loop cycles

// -------------------- Setup --------------------
void setup() {
  lcd.begin(16, 2);
  sensor1.begin();
  sensor2.begin();

  pinMode(HEATER_PIN_1, OUTPUT);
  pinMode(HEATER_PIN_2, OUTPUT);

  // Turn both heaters OFF (active LOW relay)
  digitalWrite(HEATER_PIN_1, HIGH);
  digitalWrite(HEATER_PIN_2, HIGH);

  startTime = millis();
  lastLcdInit = millis();
}

// -------------------- Loop --------------------
void loop() {
  unsigned long elapsed = millis() - startTime;

  // Determine current stage
  unsigned long accumulated = 0;
  int currentStage = -1;
  for (int i = 0; i < numStages; i++) {
    accumulated += stageDurations[i];
    if (elapsed < accumulated) {
      currentStage = i;
      break;
    }
  }

  if (currentStage != -1) {
    targetTemp = stageTemps[currentStage];
    finished = false;
  } else {
    // All stages complete - stop heating
    targetTemp = 0.0;
    finished = true;
    digitalWrite(HEATER_PIN_1, HIGH);
    digitalWrite(HEATER_PIN_2, HIGH);
  }

  // -------------------- Read temperatures --------------------
  sensor1.requestTemperatures();
  sensor2.requestTemperatures();

  float temp1 = sensor1.getTempCByIndex(0);
  float temp2 = sensor2.getTempCByIndex(0);

  // -------------------- Fault Detection --------------------
  bool sensor1Fault = (temp1 < -30.0);
  bool sensor2Fault = (temp2 < -30.0);

  if (sensor1Fault) digitalWrite(HEATER_PIN_1, HIGH);
  if (sensor2Fault) digitalWrite(HEATER_PIN_2, HIGH);

  // -------------------- Control heaters --------------------
  if (!sensor1Fault)
    heater1On = controlHeater(HEATER_PIN_1, temp1);
  else
    heater1On = false;

  if (!sensor2Fault)
    heater2On = controlHeater(HEATER_PIN_2, temp2);
  else
    heater2On = false;

  delay(100);
  // -------------------- Blink toggle every other loop --------------------
  blinkCounter++;
  if (blinkCounter >= 2) { // toggle every 2 loops (~0.5 sec at delay(250))
    blinkCounter = 0;
    blinkState = !blinkState;
  }
 
  // Re-init LCD every 10 seconds
  if (millis() - lastLcdInit >= 10000UL) {
    lcd.begin(16, 2);
    lcd.clear();
    lastLcdInit = millis();
  }

  // -------------------- Display on LCD --------------------
  lcd.setCursor(0, 0);

  // Channel 1 display
  if (heater1On && blinkState)
    lcd.print("   "); // Blink T1 off
  else
    lcd.print("T1:");

  if (sensor1Fault)
    lcd.print("ERR ");
  else
    lcd.print(temp1, 1);

  // Channel 2 display
  lcd.print(" ");
  if (heater2On && blinkState)
    lcd.print("   "); // Blink T2 off
  else
    lcd.print("T2:");

  if (sensor2Fault)
    lcd.print("ERR ");
  else
    lcd.print(temp2, 1);

  lcd.setCursor(0, 1);
  if (!finished) {
    lcd.print("MT:");
    lcd.print(targetTemp, 0);
    lcd.print("C  ");
  } else {
    lcd.print("Gatavs! ");
  }

  // Display elapsed time HH:MM:SS
  unsigned long elapsedSeconds = elapsed / 1000UL;
  unsigned int hours   = elapsedSeconds / 3600UL;
  unsigned int minutes = (elapsedSeconds % 3600UL) / 60UL;
  unsigned int seconds = elapsedSeconds % 60UL;

  if (hours < 10) lcd.print("0");
  lcd.print(hours);
  lcd.print(":");
  if (minutes < 10) lcd.print("0");
  lcd.print(minutes);
  lcd.print(":");
  if (seconds < 10) lcd.print("0");
  lcd.print(seconds);

  delay(100);
}

// -------------------- Heater Control Function --------------------
// Returns true if heater is ON
bool controlHeater(int heaterPin, float currentTemp) {
  bool isOn = false;

  if (targetTemp > 0) {
    if (currentTemp < targetTemp - 0.5) {
      digitalWrite(heaterPin, LOW);  // Turn ON (active LOW)
      isOn = true;
    } else if (currentTemp > targetTemp + 0.5) {
      digitalWrite(heaterPin, HIGH); // Turn OFF
      isOn = false;
    } else {
      // Keep current state
      isOn = (digitalRead(heaterPin) == LOW);
    }
  } else {
    digitalWrite(heaterPin, HIGH); // Force OFF
    isOn = false;
  }

  return isOn;
}